Printers are commonly used as office equipment which provides great convenience to modern offices. Existing printers include ink-jet printers and laser printers. Inkjet printers use ink cartridges as printing consumables containers to provide ink to form text or images on paper to be printed, while laser printers use toner cartridges as printing consumables containers to provide toner to form text or images on a printing media.
See FIG. 1. The existing toner cartridge has a case 11. The surroundings of the case 11 form a compartment accommodating the toner. The outer wall of the case is equipped with a chip mounting position 12. The consumables chip 13 is installed on the chip mounting position 12. The consumables chip 13 has a base plate. The base plate is equipped with two electrical contacts 14 and 15 serving as a communication unit which performs data exchange with the laser printer. Further, the other side of the base plate is provided with an electronic module (not shown in FIG. 1) which connects with the electrical contacts 14 and 15. The electronic module has a memory for storing the remaining toner level, the toner cartridge model, the laser printer model for the toner cartridge, and other data.
When toner cartridge is installed on the laser printer, the laser printer will check the consumables chip 13 to determine whether the consumables chip on the toner cartridge is suitable for the laser printer and determine whether the installed toner cartridge can work properly. The laser printer provides the consumables chip 13 with an electronic signal with specific waveform via the two electrical contacts 14 and 15 that represents a specific reading and writing information. The laser printer sends a reading command to the electronic module. After the electronic module receives the reading command, it returns a specific signal via the electrical contacts 14 and 15 to the laser printer. When the electronic module returns information to the laser printer, the waveform of the electrical contacts 14 and 15 is shown in FIG. 2.
The electrical contact 15 receives a clock signal from the laser printer. This clock signal is a reference clock signal and voltages of the high level and low level are 1.8 V and 0 V, respectively (relative to the ground of the printer). The electrical contact 14 receives the level signal from the laser printer 14. When it returns a binary number “0,” it performs the signal modulation, and when it returns is a binary number “1” it does not perform the signal modulation.
Only when the reference clock signal is low, does the laser printer receive the returned data. Therefore, when the clock signal received by the electrical contact 15 is low, the electronic module needs to perform signal modulation over the electrical contact 14. As shown in FIG. 2, when the clock signal is a first low level and the first electrical contact 14 is a high level signal, the signal is not modulated, outputting a binary number “1.” When the second clock signal is low and the electrical contact 14 is a low level signal, the signal is modulated, outputting a binary number “0”, and so on.
The electronic module does not greatly modulate the electrical contact 14 signal, in general, only 0.3 V. Therefore, the voltage of the electrical contact 14 is 5.5 V (relative to the printer ground) at a high level and 5.2 V at low level (relative to the printer ground). After the laser printer receives the electrical signal from the electrical contact 14, it demodulates the electrical signal to obtain corresponding data. The following electrical signals for the contact 15 (or the electrical contact 32) and the electrical contact 14 (or the electrical contact 31) are relative to the printer, and the other signals are relative to the ground of the chip. The ground of the chip is connected with the electrical contact 15 (or the electrical contact 32). Hereafter, the ground means the ground of the chip.
See FIG. 3. The electronic module is connected with the electrical contacts 14 and 15. The electronic module has a power circuit comprising the resistor R1 and capacitor C1. The power circuit supplies electricity to the microcontroller 16. The microcontroller 16 is equipped with a memory that stores information related to the toner cartridge.
The electronic module also comprises a modulation circuit comprising the resistors R4 and R5 and triode Q1. The base electrode of the triode Q1 is connected to the pin IO1 of the microcontroller 16 via resistor R4, and the on-or-off of the triode is controlled by the high or low level output from the pin IO1. The collector of the triode Q1 is connected to the electrical contact 14 via the resistor R5, and the emitter is grounded. When the electronic module outputs a binary number “0”, the pin IO1 of the microcontroller 16 outputs a high level, the triode Q1 is turned on, the electrical voltage of the electrical contact 14 is reduced, and therefore, the signal modulation is achieved.
When the electronic module outputs a binary number “1” or when the reference clock signal is high, the pin IO1 outputs a low level signal, the triode Q1 is turned off, and the electrical contact 14 is a high level signal.
The clock circuit of the electronic module comprises the resistors R2 and R3 and the voltage comparator G1. One end of the resistor R3 is connected to the electrical contact 14, and the other end to the point B; one end of the resistor R2 is connected to the electrical contact 15 and the other end to the point B.
The voltage comparator G1 is integrated into the voltage comparator of the microcontroller of 16, its inverting input terminal is connected to the point B via the pin 102 of microcontroller 16, and the non-inverting input terminal is connected to the reference voltage Vref. The reference voltage Vref is the internal reference voltage of the microcontroller 16. The output terminal of the voltage comparator G1 provides a synchronous clock signal to the microcontroller 16.
Because there is a voltage drop between the electrical contacts 14 and 15 and the voltage waveform of the voltage drop is an alternating signal, by selecting appropriate resistance values of the resistors R2 and R3, the voltage at point B can be a high level-low level alternating signal waveform to form a clock signal, for example, a clock signal alternating between 0.8 V and 1.3 V.
Meanwhile, an appropriate voltage in the microcontroller 16 is chosen as a reference voltage Vref of the voltage comparator G1, e.g., the reference voltage Vref can be chosen as 1 V. Because the voltage level of the clock signal inputted to the comparator G1 at point B alternates up or down between the reference voltage Vref, the voltage output terminal of the comparator G1 outputs a clock signal alternating between a high level and a low level and provides this clock signal to the microcontroller 16.
When the modulation circuit modulates the signal output of the electrical contact 14, the voltage of the electrical contact 14 will decrease by 0.3 V, and the voltage of the electrical contact 15 remains unchanged. Because of the voltage division of the resistors R2 and R3, the voltage at point B will correspondently decrease by 0.1 V, and thus it alternates between 0.7 V and 1.2 V. Because the clock signal inputted at point B is still up-down alternating around the reference voltage Vref, the signal outputted by the voltage comparator output G1 remains a high-low alternating clock signal and the amplitude level is consistent with the original.
See FIG. 4. An existing ink cartridge has a case 21; the surroundings of the case 21 form a compartment 25; and the compartment 25 contains the ink. An ink outlet 24 is installed under the case 21; the ink in the compartment 25 can flow out through the ink outlet 24. A consumables chip 23 is installed on the outer wall of the case 21. The structure of the consumables chip is shown in FIG. 5.
The consumables chip 23 comprises a base plate 26. The base plate 26 is provided with several electrical contacts 27. The electrical contact 27 is used as communication unit and is connected with the electrical contacts of the printer to exchange information. The base plate 26 is also provided with an electronic module 28. The electronic module 28 is provided with a memory. The memory stores information relating to the ink cartridge.
The electrical contact 27 includes a date contact and a clock contact. The modulation of the output electrical signal by the electronic module uses the reference clock provided by the inkjet printer as a reference base.